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Wednesday, December 7, 2016

Hepatitis A
is one of the five
hepatitis viruses that infect the liver. These viruses are a major health
problem since it can affect millions of people around the world. Although there
is a vaccine that prevents the virus, transmission is still possible especially
in countries without access to the vaccine. Out of the five hepatitis viruses,
Hepatitis A accounts for half the total number of human hepatitis infections
diagnosed worldwide. Although there is no specific treatment after contracting
the virus, there are ways of detection to help prevent it. Each year, there are
approximately 30,000
to 50,000 cases of Hepatitis A in the United States. So what are the main
sources and how do we prevent this virus?

Contaminated Produce

Hepatitis A virus is transmitted
through the ingestion of contaminated food as well as through the fecal-oral
route. Common foods associated with the virus are contaminated drinking water,
raw or undercooked shellfish from contaminated water, and raw produce. Green
vegetables are the most common produce (spinach, green onions, and lettuce) that
are contaminated with Hepatitis A virus. These produce are exported and grown
in large volumes and are commonly eaten raw in ready-to-eat salads. The virus
can enter the produce in a variety
of locations including the roots from the soil, as well as the leaves. Since
the virus is commonly found in contaminated water, washing these vegetables can
be a source of contamination. Since the produce is grown in such large numbers,
further contamination could occur during processing. Contamination could occur
in the soil where they grow, in the handling process, and when washing the vegetables.
These vegetables are often consumed raw, which makes consumers susceptible to
the Hepatitis A virus.

Prevention

Washing your hands seems like a
simple mundane task, but it is an effective method to prevent the spread of the
virus. Since the virus can often be spread through food handlers, sanitation of
hands, as well as the food plant is important. Hepatitis A has no specific
treatment and recovery can take several months. There are both mild and severe
symptoms which includes fever, diarrhea, and jaundice. To prevent exposure
to the virus, sanitation is very important. Especially when traveling to areas where
hepatitis A is common, avoid food from street vendors. Foods that are eaten
raw should be avoided since they may have been washed in contaminated water.
Food can also be cooked properly on your own to ensure proper sanitation
method.

The photo shows how the TaqMan probe is used to detect the target
Hepatitis A virus. The probe contains a reporter dye on one end, and a quencher
on the other. The reporter and quencher which are shown as the star and circle
are used together in order to emit a fluorescence when the virus is detected.
The reporter is a fluorescent molecule that monitors the PCR. As the virus is
detected, the PCR accumulates and the fluorescence increases. When the quencher
is close to the reporter (TaqMan probe is intact), it suppresses the
fluorescence. However, when the virus is detected and the probe is broke apart
and separates the reporter and quencher. This then gives of a fluorescent
light. The data can be seen with a computer and can show positive or negative
for the detection of the virus.

With the
help of this detection method, the number of Hepatitis A
cases is gradually declining. Along with the vaccine, detection methods
like this have allowed us to find the Hepatitis A virus in the vegetables
before distribution. This helps in surveillance and reduces the number of
outbreaks. The use of nested real-time PCR is a rapid method that has proven to
work with the Hepatitis A virus. Using this new technology, it can be applied
to other pathogens in order to minimize other diseases. This method can detect the
virus and therefore be able to help prevent outbreaks. I can’t wait to see what
impact this method has.

Friday, December 2, 2016

Currently, the average American throws
away approximately 185 pounds of plastic every year…that is enough to
circle the earth four times. Keep in mind that the circumference of the earth
is 24,901 miles- yikes! Plastic constitutes approximately 90% off all the trash
floating on the ocean’s surface, which can kill marine mammals. Frequently
found on the ocean are plastic water bottles, possibly because Americans
dispose of 35 billion plastic water bottles yearly. Half of the plastic used, only
gets used once, and only 5% of the plastic that gets thrown away is recovered.
The main way of recovering plastic is recycling.

Recycling reduces the amount of waste
sent to landfills and incinerators. It also prevents pollution by reducing the
need to collect new raw materials and conserves natural resources such as
timber, water, and minerals. Recycling reduces greenhouse gas emissions that
contribute to global climate change and helps sustain the environment for
future generations, all while saving energy.

In 2014, California became the first state to ban
the sale of plastic single-use bags.
San Francisco became the first jurisdiction in California to ban single-use
plastic bags, in 2007. Last year, Los Angeles, the largest city in California
and second largest in the United States, banned single-use plastic bags and
placed a 10-cent charge on paper bags. When it comes to shopping bags and water
bottles, it is advised to reuse. Although it may be easier to recycle and reuse
plastic shopping bags and water bottles, it is harder to reuse and recycle food
packaging. The plastic used for food packaging has several purposes. Most
importantly, it protects food products from distribution damage, contains the
food, and provides consumers with ingredient and nutrition information.

Really, the
overall goal of food packaging is to contain food in a cost-effective
way that satisfies industry requirements and consumer desires, maintains food
safety, and minimizes environmental impact. So what are some innovative ways to
do all of the above? Renewable plastic!

So what is renewable plastic?!

A
novel way to make plastic from carbon dioxide and inedible plant material, such
as agricultural waste and grasses has been discovered. Researchers say the new
technology could provide a low-carbon alternative to plastic bottles and other
items currently made from petroleum. The current goal is to replace
petroleum-derived products with plastic made from CO2. Scientists from Stanford believe that by changing the formula for
plastic by using Earth-friendly materials to create plastic, the goal will be
feasible. Many plastic products today are made from a polymer called
polyethylene terephthalate (PET), also known as polyester. PET is made from two
components, terephthalic acid and ethylene glycol, which are derived from
refined petroleum and natural gas. Manufacturing PET produces significant
amounts of CO2, a greenhouse gas that contributes to global warming.
A promising alternative to PET called polyethylene furandicarboxylate (PEF). PEF is made from ethylene glycol and a compound called
2-5-Furandicarboxylic acid (FDCA). PEF is an attractive replacement for PET
because FDCA can be sourced from biomass instead of petroleum. Despite the many
desirable attributes of PEF, the plastics industry has yet to find a low-cost
way to manufacture it at scale. One approach is to convert fructose into FDCA from
corn syrup. A better alternative is to make FDCA from inedible biomass, like
grasses or waste material left over after harvest, such as furfural, a compound
made from agricultural waste. However, making FDCA from furfural and CO2
typically requires hazardous chemicals (carbonate) that are expensive and
energy-intensive to make. By combining carbonate with CO2 and furoic
acid, a molten salt is formed which becomes the starting material for FDCA. The
next step, transforming FDCA into PEF plastic, is a straightforward process
that has been worked out by other researchers.

Chemistry
can unlock the promise of PEF that has yet to be realized. This is just the
first step. Some work still needs to be done to see if it is viable at scale
and to quantify the carbon footprint. But as of now PEF has the potential to
significantly reduce greenhouse emissions as it is made entirely from vegetable raw materials and CO2. Not only is PEF considered to be the
packaging material of the future, particularly for food and beverages, but PEF can
also be recycled or converted back to atmospheric CO2 by
incineration. Eventually, that CO2 will be taken up by grass, weeds
and other renewable plants, which can then be used to make more PEF. Lastly,
PEF promises a greater level of impermeability to carbon dioxide and oxygen,
thus ensuring a longer shelf life of packaged products. Overall, by providing a
low-carbon and petroleum alternative to plastic packaging, PEF is looking like
a promising replacement for polyethylene terephthalate due to the potential of
reducing greenhouse emissions by a drastic measure. PEF will proved package
modernization for consumer convenience, along with a makeover healthy to the
environment- a double win!